Backup BigQuery Views and Scheduled Queries to a Git repository using Python. Full article on stacktonic.com

google_bigquery_backup_views_scheduled_queries_git.py

############################################################
# Author    Krisjan Oldekamp / Stacktonic.com              
# Email     krisjan@stacktonic.com                         
# Article   https://stacktonic.com/article/backup-your-valuable-big-query-views-and-scheduled-queries-using-python
############################################################

import os
import git
import google.oauth2.service_account
from google.cloud import bigquery
from google.cloud import bigquery_datatransfer # Also enable the Data Transfer API in the GCP console

############################################################
# Settings

LOCAL_PATH_BACKUP = "./gcp-bigquery-sql-backup/" # Backup directory (end with a trailing /). When REPO_COMMIT is set to True, this folder will also be used to clone and commit to the Git repository

REPO_COMMIT = True # When set to True, the script will clone the Git repository specified in the REPO_LINK setting. Then it will delete all the folders in the repo, download the latest version of the views and scheduled queries to the repo and commits the changes.
REPO_LINK = "git@bitbucket.org..." # Repository link
REPO_KEY_PATH = "../.ssh/..." # Path to SSH private key used for authentication with the repository. Leave empty when not using an SSH key.

GCP_JSON_KEYPATH = "your-keyfile.json" # Path to JSON keyfile for Service Account

# You can specify multiple projects. The location / region is required for downloading scheduled query SQL.
GCP_PROJECTS_BACKUP = [
    {
        "project_id": "your-gcp-project-id",
        "location": "europe" # See the "region" column in the GCP scheduled query interface
    }
]

# End of settings
############################################################

# Authenticate use a Service account / JSON keyfile
def get_credentials(keyfile_json):
    scopes=['https://www.googleapis.com/auth/bigquery']

    return (
        google.oauth2.service_account.Credentials.from_service_account_file(keyfile_json, scopes=scopes)
    )

# Format scheduled query name so it can be used in a filename
def format_name(name):
    return name.lower().replace(" ", "_")

# Push commit to repository
def git_push_commit(repo, repo_key_path, repo_local_path):
    try:
        if repo_key_path == "":
            repo.git.add(all=True)
            repo.index.commit("Automated commit containing changes to BigQuery views and scheduled queries.")
            repo.remotes.origin.push()
        else:
            with git.Git().custom_environment(GIT_SSH_COMMAND="ssh -i " + repo_key_path):
                repo.git.add(all=True)
                repo.index.commit("Automated commit containing changes to BigQuery views and scheduled queries.")
                repo.remotes.origin.push()
    except:
        print("Some error occured while pushing the commit")    

# Save Google BigQuery views to local filesystem
def save_bigquery_views(credentials, project_id, path):
    
    client_bq = bigquery.Client(credentials=credentials, project=project_id)
    datasets = list(client_bq.list_datasets())
    cnt_views = 0

    # Loop datasets
    if datasets: 
        for dataset in datasets: 
            dataset_name = dataset.dataset_id
            dataset_ref = dataset.reference
            tables = list(client_bq.list_tables(dataset_ref))

            # Loop tables in dataset
            for table in tables:
                # Only select VIEW
                if table.table_type == "VIEW":
                    table_name = table.table_id
                    table_ref = dataset_ref.table(table_name)
                    table = client_bq.get_table(table_ref)
                    
                    backup_directory = path + project_id + "/bq_views/" + dataset_name
                    if not os.path.exists(backup_directory):
                        os.makedirs(backup_directory) # Create directory when it doesn't exist
                    
                    # Save view SQL to file
                    f = open(backup_directory + "/" + table_name + ".sql", "w+") # Save view SQL to file
                    f.write(table.view_query)
                    cnt_views+=1

    return cnt_views

# Save Google BigQuery scheduled queries to local filesystem   
def save_bigquery_scheduled_queries(credentials, project_id, location, path):
    
    client_bq_df = bigquery_datatransfer.DataTransferServiceClient(credentials=credentials)
    parent = "projects/{}/locations/{}".format(project_id, location)
    cnt_scheduled_queries = 0

    # Loop all Data Transfer elements in project
    for element in client_bq_df.list_transfer_configs(parent):
        
        scheduled_query_name = format_name(element.display_name)
        scheduled_query_sql = ""
        
        # Loop over Data Transfer parameters, select scheduled queries and get query SQL
        params = element.params.items()
        for key, value in params: 
            if key == "query":
                scheduled_query_sql = value

        backup_directory = path + project_id + "/bq_scheduled_queries/"
        if not os.path.exists(backup_directory): # Create directory when it doesn't exist
            os.makedirs(backup_directory)

        # Write to file
        f = open(backup_directory + "/" + scheduled_query_name + ".sql", "w+")
        f.write(scheduled_query_sql)
        cnt_scheduled_queries+=1

    return cnt_scheduled_queries

def execute():
    
    credentials = get_credentials(GCP_JSON_KEYPATH)
    
    print ("Found {} GCP projects in settings".format(len(GCP_PROJECTS_BACKUP)))

    if REPO_COMMIT:
        # Clone repository if Git commits are enabled
        print("Git commits enabled. Cloning repository {} to {}".format(REPO_LINK, LOCAL_PATH_BACKUP))
        
        # Delete folder / repository when existing
        if os.path.exists(LOCAL_PATH_BACKUP):
            git.rmtree(LOCAL_PATH_BACKUP)
        
        if REPO_KEY_PATH == "":
            repo = git.Repo.clone_from(REPO_LINK, LOCAL_PATH_BACKUP)     
        else:
            repo = git.Repo.clone_from(REPO_LINK, LOCAL_PATH_BACKUP, env={"GIT_SSH_COMMAND": "ssh -i " + REPO_KEY_PATH}) # Use SSH key
    
        # Remove old backups in repository
        repo_dirs = next(os.walk(LOCAL_PATH_BACKUP))[1]
        for dir in repo_dirs:
            if not dir.startswith("."):
                git.rmtree(os.path.join(LOCAL_PATH_BACKUP, dir))
    else:
        # Only download to local filesystem. Create directory when it doesn't exist
        if not os.path.exists(LOCAL_PATH_BACKUP):
            os.makedirs(LOCAL_PATH_BACKUP)

    # Loop through GCP project and save views and scheduled queries
    for i, project in enumerate(GCP_PROJECTS_BACKUP):

        print ("-- Starting backup for project: {}".format(project["project_id"]))
        
        views = save_bigquery_views(
            credentials, 
            project["project_id"], 
            LOCAL_PATH_BACKUP
        )
        print("# {} views saved..".format(views))

        scheduled_queries = save_bigquery_scheduled_queries(
            credentials, project["project_id"], 
            project["location"], 
            LOCAL_PATH_BACKUP
        )
        print("# {} scheduled queries saved..".format(scheduled_queries))

    # Push code to remote repository
    if REPO_COMMIT:
        git_push_commit(repo, REPO_KEY_PATH, LOCAL_PATH_BACKUP)
        print("Pushed code to repository..")

    print("Done.")
       
execute()